The overall objectives of the Morphology Core have not changed: to facilitate research in reproductive biology by providing investigators the ability to combine morphologic with endocrinologic, cellular and/or molecular approaches; and importantly, to encourage collaboration among associates with common interests in the reproductive sciences who represent several divisions of the University (School of Medicine, School of Hygiene and Public Health, and School of Arts and Sciences). The Core has evolved to offer expertise in immunocytochemistry, immunofluorescence, analytical methods for the quantification of signal density, stereological methods for the quantifiation of cells and cell ultrastructure and in situ hybridization. PCR-based in situ hybridization was also considered seriously, and is now underway. With the realization that it would not be possible to offer this wide variety of services without increased staff, and, moreover, that it often is in the best interests of investigators to perform their own studies independently, the training of associates and their staffs in morphological methods has become an increasingly central function of the Lab. As most investigators cannot afford the expensive equipment that morphological studies require, the Core also provides investigators the ability to use the equipment and space as needed, without charge, and continues to provide expert advice on the design and conduct of experiments, and on the interpretation of results.